Estimation of Sum:
1. 3256 + 2178:
- Estimate each number to the nearest thousand: 3256 ≈ 3000 and 2178 ≈ 2000
- Add the estimated numbers: 3000 + 2000 = 5000
2. 9023 + 1555:
- Estimate each number to the nearest thousand: 9023 ≈ 9000 and 1555 ≈ 2000
- Add the estimated numbers: 9000 + 2000 = 11000
3. 2987 + 1545:
- Estimate each number to the nearest thousand: 2987 ≈ 3000 and 1545 ≈ 2000
- Add the estimated numbers: 3000 + 2000 = 5000
4. 56234 + 4567:
- Estimate each number to the nearest ten thousand: 56234 ≈ 60000 and 4567 ≈ 5000
- Add the estimated numbers: 60000 + 5000 = 65000
Therefore, the estimated sum of 3256 + 2178 + 9023 + 1555 + 2987 + 1545 + 56234 + 4567 is approximately 87500.
By rounding each number to the nearest thousand or ten thousand, we can quickly estimate the sum without needing to calculate exact values. This method is useful for getting a rough estimate of the total without spending too much time on precise calculations.